KR20170141126A - Process and absorbent for dehumidifying moist gas mixtures - Google Patents

Abstract

The present invention relates to a method for dehumidifying a moist gas mixture, wherein the moist gas mixture comes in contact with an absorbent comprising dialkylimidazolium salt and trialkyl phosphate. In addition, the present invention also relates to an absorption heat pump comprising an absorbent according to the invention, and to the absorbent itself according to the invention.

Description

PROCESS AND ABSORBENT FOR DEHUMIDIFIING MOIST GAS MIXTURES < RTI ID = 0.0 >

The present invention relates to a method for dehumidifying a wet gas mixture, wherein the wet gas mixture is contacted with an absorbent comprising a dialkylimidazolium salt and a trialkylphosphate. In addition, the present invention also relates to an absorption heat pump comprising an absorbent according to the invention, and to the absorbent itself according to the invention.

Dehumidification of the wet gas mixture is necessary in many technical fields.

For example, ventilation and air conditioning of a building or vehicle typically requires dehumidification of the air as well as cooling, since the temperature will drop below the dew point temperature while the cooled air is often too humid to cool to the desired temperature. Thus, dehumidification of air in a conventional air conditioning system accounts for most of the electricity consumption.

The electrical consumption of the building air conditioning system is reduced by dehumidifying the air by adsorption or absorption of water using a drying medium and then regenerating by heating the water-containing drying medium to a temperature at which water is desorbed again. Compared to adsorption on a solid adsorbent, the advantage of absorption in a liquid absorption medium is that the air dehumidification can be performed with reduced equipment complexity and less drying medium, and the regeneration of the water-containing drying medium can be carried out using solar heat It is easier.

A further technical field in which dehumidification of the wet gas mixture is used is the absorption chiller (principle described in WO 2014/079675 A1, "absorption chiller" is used interchangeably with "absorption chiller" according to the invention) . Here, the wet gas mixture is formed during the evaporation of water under low pressure. The water vapor thus formed needs to be removed from the mixture so that the wet gas mixture can be returned to water evaporation and pass through a new cycle. Here again, the absorption in the liquid absorption medium is advantageous compared to the adsorption on the solid adsorption medium.

In addition to its use in absorption chillers, there is still a further area where drying of the gas stream is required. This is natural gas refining, which applies other requirements for the ionic liquids used for it.

In order to absorb moisture with the aid of ionic liquids, a series of ionic liquids have been proposed in the prior art. Thus, DE 10 2010 004 779 A1 discloses, for example, 1-ethyl-3-methylimidazolium ethylsulfate, 1-ethyl-3-methylimidazolium methylsulfate, Ethyl-3-methylimidazolium methylsulfonate, 1-butyl-3-methylimidazolium bistrifluoromethanesulfonimide, 1-butyl-3-ethylimidazolium chloride .

CN 102335545 A discloses a series of ionic liquids based on alkyl phosphates, in particular 1,3-dimethylimidazolium dimethylphosphate, 1-ethyl-3-methylimidazolium dimethylphosphate and 1-butyl- Lt; / RTI > dimethylphosphate.

Y. Luo et al., Appl. Thermal Eng. 31 (2011) 2772-2777], it has been proposed to use ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate in place of lithium bromide aqueous solution for air dehumidification. However, such ionic liquids have the disadvantage of merely insufficient absorption capacity.

Y. Luo et al., Solar Energy 86 (2012) 2718-2724) discloses an ionic liquid 1,3-dimethylimidazolium acetate as an alternative to 1-ethyl-3-methylimidazolium tetrafluoroborate for air dehumidification Has been proposed. The acetate is also described in M. M. < RTI ID = 0.0 > Kanakubo et al., J. Mol. Liq. 217 (2016) 112-119.

US 2011/0247494 A1 proposes a further ionic liquid for this purpose, namely 1-ethyl-3-methylimidazolium acetate.

The application of these ionic liquids in an absorption chiller is also discussed in WO 2013/050242 A1.

While these ionic liquids described in the prior art are highly suitable for dehumidification, ionic liquids containing dialkylimidazolium ions have the disadvantage that, on contact with the gas mixture, . This is especially so in the case of dehumidification of indoor air, and is not desirable for absorption type coolers such as refrigerators. Accordingly, an absorbent which can minimize the contamination is sought.

For this reason, the object of the present invention was to provide an absorbent which is particularly prone to release odorous substances therefrom.

Surprisingly, absorptive media have been found which achieve the above objects.

Accordingly, the present invention, at least one trialkyl phosphate and Q ⁺ A of the wet gas mixture G _1, the following structures ^{(I) -, Q + (} R 1 O) 2 PO 2 -, (Q +) 2 R 2 OPO ₃ ^{2 -} and _{^{Q + M + R 3 OPO 3}} 2 - in contact with the liquid absorbing medium a ₁ comprising a mixture of at least one salt S is selected from the group consisting of lower water as compared to the humid gas mixture G ₁ a method for dehumidifying the gaseous mixture having a content of G _2, and, as compared to the liquid absorbing medium a ₁ for obtaining the liquid absorption medium a ₂ having an elevated water content, the wet gas mixture G _1,

Wherein Q ^& lt ^{; +} > is a dialkyl imidazolium cation in which the alkyl groups are each independently of one to ten carbon atoms,

A ^- is R ^* COO ^- is an anion selected from the group consisting _{^{of, -, R'SO 3 -, HSO}} 4 - , and R _"4 SO

R ^* , R ', R ", R ^A , R ^B and R ^C are each independently an alkyl group having from 1 to 10 carbon atoms,

R ¹ , R ² and R ³ are each independently an alkyl group, especially having 1 to 10 carbon atoms,

M ⁺ is an alkali metal ion, preferably Li ⁺ , K ⁺ or Na ⁺ , more preferably K ⁺ or Na ⁺ .

"Wet" should be understood to mean "water, especially water vapor" in the present invention. "Dehumidification" should be understood to mean at least partially removing water.

It should be understood that "at least partially" means "partially or completely" in the present invention.

Thus, the term "wet gas mixture G ₁ " is used in the present invention to mean that the gas mixture G ₁ comprises water, preferably water vapor ("water vapor" should be understood to mean water in the vapor phase physical state) But is not to be construed as being limited otherwise in particular. The water content of the wet gas mixture is not particularly limited at all, in particular 0.01 vol% to 99.99 vol% ("vol%" represents the volume of water vapor based on the total volume of the wet gas mixture G ₁ ). The composition of the wet gas mixture G ₁ may vary according to the application of the method according to the invention. The wet gas mixture G ₁ is selected in particular from wet natural gas, wet air (which may be wet or wet room air resulting from evaporation of water in an absorption chiller), preferably wet air. In the case of wet natural gas, the water content is in particular from 0.01 vol% to 15.00 vol%, in the case of humid air, the content is in particular from 0.01 vol% to 15.00 vol%, in the case of wet room air, or in particular from 95.00 vol% to 99.99 vol% Which is the preferred range when it relates to wet air resulting from evaporation of water in the cooler).

The wet gas mixture G ₁ used in the _process has a temperature of from 2 캜 to 100 캜, preferably from 3 캜 to 60 캜, more preferably from 4 캜 to 50 캜, even more preferably from 5 캜 to 40 캜 , And is not particularly limited at all. However, since the absorption capacity is very good in this temperature range, the process according to the invention is particularly suitable for the dehumidification of the natural gas, in which processing of the gas often occurs in this temperature range.

In the process according to the invention, the absorption medium A ₁ is also preferably further heated to a temperature of from 10 캜 to 100 캜, preferably from 15 캜 to 80 캜, more preferably from 20 캜 to 50 캜, Lt; 0 > C.

The contact may be carried out in any manner known to those of ordinary skill in the relevant art, especially in the water absorption unit W _abs1 (described below). The contact causes the absorption medium A ₁ to at least partially absorb water, i.e. water, from the wet gas stream gas mixture G ₁ .

The method according to the invention is carried out in particular in apparatus V ₁ . The device V ₁ is limited to such a degree that it is suitable for carrying out the method according to the present invention. In particular, a device V ₁ comprising the following components may be used:

(i) at least one water absorption unit W _abs1 set up for contacting the wet gas mixture with a liquid absorption medium, in particular A < _{1 >} .

The device V ₁ also optionally comprises the following components:

(ii) at least one water desorption unit W _des1 comprising a heat exchanger W _x1 and set up to at least partially remove water from the liquid absorption medium, in particular A ₂ , and

(iii) with a water absorption unit W _abs1 associated with water desorption unit _des1 W and to rotate the liquid absorption medium, in particular, A ₁ and A ₂ circuit U _1.

Thus, the method according to the invention can be carried out in a water absorption unit W _abs1 familiar to a person skilled in the art. The usable water absorption unit W _abs1 comprises a water absorber, which is known to the person skilled in the art in particular. The absorber is based on the principle of increasing the surface area of the liquid absorbing medium A ₁ and simultaneously achieving the maximum residence time of the liquid absorbing medium A _{1 in} the water absorber during water absorption. In particular, it is possible to use a combination of a packed bed, a spray column, a drop-film, a bubble column, a tray column, a wet scrubber (e.g. Venturi scrubber) It is possible to use a water absorber selected from the group. Drop-film, especially shell and tube drop-use of the film as a water absorber is particularly preferred. The water absorption unit W _abs1 may also further comprise an additional heat exchanger W _z1 set up so that the liquid absorption medium A ₁ is adjustable to the desired temperature.

In a water desorption unit W _des1 comprising a heat exchanger W _x1 , it can again be taken off to a water-containing liquid absorption medium, in particular A ₂ . Water desorption unit _des1 W is a water-containing liquid absorption media, in particular to supply heat to A _2, a water-containing and increasing the surface area of the liquid absorption medium A _1, at the same time water desorption unit W _des1 Is based on the principle of achieving the longest possible residence time of the water-containing liquid absorbing medium, in particular A ₂ .

The usable water desorption unit W _des1 , including the heat exchanger W _x1 , is particularly suitable for the combination of heat exchangers and water desorbers known to those of ordinary skill in the relevant art, especially upstream heat exchangers, in particular shell and tube heat exchangers, plates and a horizontal tube evaporator having a frame and a frame heat exchanger. Further, the water desorption unit W _des1 including the heat exchanger W _x1 may be a water desorber having an integrated heat exchanger. Such water desorberers with integrated heat exchangers are in particular climbing film evaporators, long tube vertical evaporators, short tube vertical evaporators, forced circulation evaporators and stirred thin film evaporators. It is particularly preferred to use the drop-film, especially the shell and tube drop-film, as the water desorption unit W _des1 .

In the circuit U ₁ , in particular the water-containing liquid absorption medium A ₂ from the water absorption unit W _abs1 is guided to the water desorption unit W _des1 , and even more preferably (in particular when the process according to the invention is carried out continuously ), the liquid absorbent of the water from the desorption unit _des1 W is guided to the water absorption unit W _abs1.

In particular, the circuit U ₁ is selected from the group consisting of conduits, in particular tubes and hoses.

In a further preferred embodiment, the circuit U ₁ also comprises a pump.

This much water as possible from the wet mixture of gas G ₁ to be absorbed, it is desirable to cool the absorption medium A ₁ while in contact with the wet gas mixture G _1. This can be achieved, for example, through an additional heat exchanger W _z1 in the water absorption unit W _abs1 .

In the process according to the invention, the wet gas mixture G ₁ is reacted with at least one trialkyl phosphate of the following structure (I) and Q ⁺ A ^- , Q ⁺ (R ¹ O) ₂ PO ₂ ^- , (Q ⁺ ) ₂ R ² OPO ₃ ^{2 -} and _{^{Q + M + R 3 OPO 3}} 2 - in contact with the liquid absorbing medium a _1, including at least one salt S mixture of selected from the group consisting of a wet gas mixture to a lower compared to the G ₁ A gas mixture G ₂ having a water content, and a liquid absorbing medium A ₂ having an increased water content as compared with the liquid absorbing medium A ₁ ,

Here, Q ^& lt ^{; +} & gt ^; is particularly preferably an alkyl group having 1 to 10, preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 4, still more preferably 1 Or a dialkylimidazolium cation having two carbon atoms,

A ^- is R ^* COO ^- is an anion selected from the group consisting _{^{of, -, R'SO 3 -, HSO}} 4 - , and R _"4 SO

R ^* , R ', R ", R ^A , R ^B , R ^C , R ¹ , R ² and R ³ are each independently preferably 1 to 10, preferably 1 to 8, More preferably 1 to 4, still more preferably 1 or 2 carbon atoms,

M ⁺ is an alkali metal ion, preferably Li ⁺ , K ⁺ or Na ⁺ , more preferably K ⁺ or Na ⁺ .

In a preferred embodiment of the process according to the invention, the salt S is selected from the group consisting of Q ⁺ A ^- and Q ⁺ (R ¹ O) ₂ PO ₂ ^- , wherein Q ⁺ , preferably one to four, more preferably one or two, and dialkylimidazolium cation having a carbon atoms, a ^- is R ^* COO ^- consisting of ^-, R'SO ₃ ^-, and R _"4 SO an anion selected from the group, R ^*, R ^1, R ', R ", R ^a, R ^B and R ^C are each independently 1 to 6, preferably 1 to 4, more preferably 1 or 2 Lt; / RTI > carbon atoms.

In a more preferred embodiment of the process according to the invention, the salt S has the formula Q ⁺ (R ¹ O) ₂ PO ₂ ^- , Q ⁺ is a dialkylimidazolium cation in which the alkyl groups are each independently methyl or ethyl , R ¹ , R ^A , R ^B and R ^C are each independently methyl or ethyl.

In a more preferred embodiment of the process according to the invention, the salt S has the formula Q ⁺ (R ¹ O) ₂ PO ₂ ^- , Q ⁺ is 1,3-dimethylimidazolium, And 1-ethyl-3-methylimidazolium, and R ^A , R ^B , R ^C And R < ¹ > are each independently methyl or ethyl. Subsequently, still more preferably, Q ⁺ is 1-ethyl-3-methylimidazolium and R ^A , R ^B , R ^C And R < ¹ > are each independently methyl or ethyl.

In addition, in all of the above embodiments of the process according to the invention it is particularly preferred that R ^A , R ^B and R ^C are each independently selected from methyl and ethyl, more preferably R ^A = R ^B = R ^C = methyl or R ^A = R ^B = R ^C = ethyl, particularly preferably R ^A = R ^B = R ^C = ethyl.

The liquid absorption medium A ₁ can be used in the form of a pure mixture of the trialkyl phosphate of structure (I) and the salt S in the process according to the invention. Alternatively, and more preferably in the process according to the invention, the liquid absorbing medium A ₁ has a total weight of at least 65% by weight, based on the total weight of the aqueous solution, of the total weight of trialkyl phosphates and all salts S, To 95% by weight. Even more preferably, the total weight of trialkylphosphate and all salts S of all structures (I) in A < ₁ > is in the range of from 70 wt% to 90 wt% based on the total weight of the aqueous solution, To 87% by weight.

In the process according to the invention, the ratio of the trialkylphosphate to the salt S of all structures (I) in the absorption medium A ₁ is not further restricted at all. However, in the process according to the invention, the ratio of the total weight of trialkylphosphate of all structures (I) to the total weight of all salts S is from 1: 9999 to 1: 9, more preferably from 1: 9999 to 1:99 more preferably from 1: 9999 to 1: it is preferred to use a range of a ₁ of the absorbing medium 999.

Then, a gas having a lower water content to yield in the process according to the invention is compared with a wet gas mixture G ₁ mixture G ₂ represents a dehumidified gas stream, which is supplied to the power generation (power generation) In the case of dehumidified gas .

The liquid absorbing medium A ₂ obtained in the method according to the present invention has an increased water content as compared to the liquid absorbing medium A ₁ . It will be appreciated that in view of the trialkylphosphate of structure (I) contained therein and in view of the salt S contained therein, A ₂ is identical to A _1, and preferably is distinguished only by its water content.

In a preferred embodiment of the process according to the invention, then from a further step in [should be understood "optionally step b)", the process according to the invention In this connection a "step a)"], the liquid absorbing medium A ₂ It is practiced to at least partially remove the water to obtain a liquid absorbing medium A ₃ having a lower water content as compared with the liquid absorbing medium A ₂ . Here, heat is further supplied to the liquid absorbing medium A ₂ . The supply of heat and at least partial removal can be effected in any manner known to those of ordinary skill in the relevant art, particularly in the water desorption unit W _des1 including the heat exchanger W _x1 . When at least partially removing the water from the liquid absorption medium A _2, A ₃ a liquid absorbing medium having a lower water content compared to the liquid absorbing medium A ₂ is obtained.

In view of the trialkylphosphate of structure (I) contained therein and in view of the salt S contained therein, it will be appreciated that the liquid absorbing medium A ₃ is identical to A _2, and is preferably distinguished only by its water content .

In a further preferred embodiment, the process according to the invention is carried out continuously. This is particularly the case in which steps a) and b) are carried out at least once after step b), and the liquid absorbing medium A ₁ used in step a), which is further carried out in each case, The water content of the liquid absorbing medium A ₃ from the liquid absorbing medium A ₁ used in at least a part of the obtained liquid absorbing medium A ₃ (that is, in particular, in step a) which was further carried out in each case and the immediately preceding step b) Is the same).

In this embodiment, it is more preferable that the liquid absorbing medium A ₂ is supplied with heat from the liquid absorbing medium A ₃ . This may be done in an additional heat exchanger W _y1 , in particular a shell and tube heat exchanger and a plate and frame heat exchanger. This makes it possible to carry out the process according to the invention in a particularly energy efficient manner.

The invention also provides, in a further aspect,

(i) to structure (I) at least one trialkyl phosphate and Q ⁺ A a ^{-, Q + (R 1 O} ) 2 PO 2 -, (Q +) 2 R 2 OPO 3 2 - and Q ⁺ M ⁺ R _³ OPO ^{3 2 -} a liquid absorbing medium containing at least one salt selected from the group consisting of a mixture of S _{1 *,}

(ii) wet gas mixture to the liquid absorbing medium A _{1 *} at least one of the water absorption unit in order to set up contact with the W _abs2,

(iii) at least one water desorption unit W _des2 set up to at least partially remove water from the liquid absorption medium A _{1 *} , comprising a heat exchanger W _x2 , and

(iv) a circuit U ₂ capable of connecting the water absorption unit W _abs2 to the water desorption unit W _des2 and circulating the liquid absorption medium A _{1 *}

, A device V ₂ for dehumidifying a humidified gas mixture, in particular humid air,

Q ^& lt ^{; + &} gt ^; is particularly preferably an alkyl group having 1 to 10, preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 4, still more preferably 1 or 2, Lt; / RTI > is a dialkyl imidazolium cation having one to twenty carbon atoms,

A ^- is R ^* COO ^- is an anion selected from the group consisting _{^{of, -, R'SO 3 -, HSO}} 4 - , and R _"4 SO

R ^* , R ', R ", R ^A , R ^B , R ^C , R ¹ , R ² and R ³ are each independently preferably 1 to 10, preferably 1 to 8, More preferably 1 to 4, still more preferably 1 or 2 carbon atoms,

M ⁺ is alkali metal ion, preferably, to a Li ^+, K ⁺ or Na ^+, and more preferably the device V ₂ characterized in that the K ⁺ or Na ^+.

The device V ₂ according to the invention is suitable for dehumidifying a wet gas mixture, in particular humid air. The device comprises the following components:

First as a component, device, V ₂ is, to at least one trialkyl phosphate and Q ⁺ A of structure (I) according to the invention ^{-, Q + (R 1 O} ) 2 PO 2 -, (Q +) 2 R ² OPO ₃ ^{2 -} and _{^{Q + M + R 3 OPO 3}} 2 - and comprising at least one salt mixture a ₁ S _* liquid absorbing medium containing between selected from the group consisting of,

Q ^& lt ^{; + &} gt ^; is particularly preferably an alkyl group having 1 to 10, preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 4, still more preferably 1 or 2, Lt; / RTI > is a dialkyl imidazolium cation having one to twenty carbon atoms,

A ^- is R ^* COO ^- is an anion selected from the group consisting _{^{of, -, R'SO 3 -, HSO}} 4 - , and R _"4 SO

R ^* , R ', R ", R ^A , R ^B , R ^C , R ¹ , R ² and R ³ are each independently preferably 1 to 10, preferably 1 to 8, More preferably 1 to 4, still more preferably 1 or 2 carbon atoms,

M ⁺ is an alkali metal ion, preferably Li ⁺ , K ⁺ or Na ⁺ , more preferably K ⁺ or Na ⁺ .

In a preferred embodiment of the device V ₂ according to the invention, the salt S in A _{1 *} is selected from the group consisting of Q ⁺ A ^- and Q ⁺ (R ¹ O) ₂ PO ₂ ^- , Q ⁺ independently 1 to 6, more preferably 1 to 4, more preferably dialkyl imidazolium cation having 1 or 2 carbon atoms, a ^- is R ^* COO ^-, R'SO ₃ ^-, and R "SO ₄ ^-, and anions selected from the group consisting of, R ^*, R ^1, R ', R", R ^a, R ^B and R ^C are each independently one to six, preferably from one 1 to 4, more Preferably an alkyl group having 1 or 2 carbon atoms.

In a more preferred embodiment of the device V ₂ according to the invention, the salt S in A _{1 *} has the formula Q ⁺ (R ¹ O) ₂ PO ₂ ^- , wherein Q ⁺ is a divalent group wherein the alkyl groups are each independently methyl or ethyl Alkyl imidazolium cation, and R ¹ , R ^A , R ^B and R ^C are each independently methyl or ethyl.

In a more preferred embodiment of the device V ₂ according to the invention, the salt S in A _{1 *} has the formula Q ⁺ (R ¹ O) ₂ PO ₂ ^- , Q ⁺ is 1,3-dimethylimidazolium, 1 , 3-diethylimidazolium, and 1-ethyl-3-methylimidazolium, and R ^A , R ^B , R ^C And R < ¹ > are each independently methyl or ethyl. Subsequently, still more preferably, Q ⁺ is 1-ethyl-3-methylimidazolium and R ^A , R ^B , R ^C And R < ¹ > are each independently methyl or ethyl.

Furthermore, in all the above-mentioned embodiments of the apparatus V ₂ according to the present invention, it is particularly preferred that A _{1 *} R ^A , R ^B and R ^C are each independently selected from methyl and ethyl, more preferably R ^A = R ^B = R ^C = methyl or R ^A = R ^B = R ^C = ethyl, particularly preferably R ^A = R ^B = R ^C = ethyl.

The liquid absorption medium A _{1 *} can be used in the form of a pure mixture of the trialkyl phosphate of structure (I) and the salt S in the process according to the invention. Alternatively, and more preferably, in the process according to the invention, the liquid absorbing medium A _{1 *} has a total weight of trialkyl phosphate and all salts S, especially of all structures (I), of 65 wt. % ≪ / RTI > to 95% by weight. Even more preferably, the total weight of trialkylphosphate and all salts S of all structures (I) in A < _{1 > * is} in the range of from 70 wt% to 90 wt% based on the total weight of the aqueous solution, By weight to 87% by weight.

The ratio of the trialkylphosphate to the salt S of all structures (I) in the liquid absorbing medium A _{1 *} is not further restricted at all. However, in the apparatus V ₂ according to the invention, the ratio of the total weight of trialkylphosphate of all structures (I) to the total weight of all salts S is from 1: 9999 to 1: 9, more preferably from 1: 9999 to 1:99 it is preferable to use an absorption medium in the range of 999 a _{* 1:,} more preferably from 1: 9999 to 1.

As a second component, the device V ₂ according to the invention comprises a water absorption unit W _abs2 set up to bring the wet gas mixture into contact with the liquid absorption medium A _{1 *} . The water absorption unit W _abs2 may in particular comprise an additional heat exchanger W _z2 set up so that the liquid absorption medium A _{1 *} can be cooled. An available water absorption unit W _abs2 of this type includes a water absorber particularly known to those of ordinary skill in the relevant art. The absorber is based on the principle of increasing the surface area of the liquid absorbing medium A _{1 *} and simultaneously achieving the maximum residence time of the liquid absorbing medium A _{1 * in} the water absorber during water absorption. Here, it is particularly possible to use a water absorber selected from the group of a packed bed, a spray column, a drop-film, a bubble column, a tray column, a wet scrubber (for example a venturi scrubber), a stirring tank and a combination of these absorbers. It is particularly preferred to use drop-film, especially shell and tube drop-film, as a water absorber.

As a third component, the device V ₂ according to the invention comprises a water desorption unit W _des2 comprising a heat exchanger W _x2 and set up to at least partially remove water from the liquid absorption medium A _{1 *} . In particular, a combination of water desorbers and heat exchangers known to those of ordinary skill in the relevant art can be used for that. Water desorption unit W _des2, the liquid absorption medium A _{1 *} sikimyeo supplying heat, and increase the surface area of the liquid absorption medium A _{1 *,} at the same time water desorption unit the liquid absorption medium A _{1 *} for achieving the longest residence time as possible to It is based on principles.

The available water desorption unit W _des2 , including the heat exchanger W _x2 , is particularly suitable for use with a combination of water desorbers and heat exchangers known in the prior art, particularly upstream heat exchangers, particularly shell and tube heat exchangers, And a horizontal tube evaporator having a frame heat exchanger. Further, the water desorption unit W _des2 including the heat exchanger W _x2 may be a water desorber having an integrated heat exchanger. Such water desorbers with integrated heat exchangers are, in particular, climbing film evaporators, long tube vertical evaporators, short tube vertical evaporators, forced circulation evaporators and stirred thin film evaporators. It is particularly preferred to use a falling-film, especially a shell and tube drop-film, as the water desorption unit W _des2 .

As a fourth component, the apparatus V ₂ according to the invention comprises a circuit U ₂ which connects the water absorption unit W _abs2 to the water desorption unit W _des2 and circulates the liquid absorption medium A _{1 *} . Circuit U ₂ will preferably selected from the group consisting of conduits, more preferably, tube and hose. In a further preferred embodiment, the circuit U ₂ also comprises a pump.

In a preferred embodiment, the apparatus V ₂ comprises an additional heat exchanger W _y2 (in addition to the heat exchanger W _x2 included in the water desorption unit W _des2 ). Heat exchangers W _y2 is, from the water absorption unit W _abs2 is set up so that the liquid absorption medium A _{1 *} is sent to water desorption unit W _des2 the heat from the liquid absorption medium A _{1 *} to be supplied, the medium is water desorption unit W _des2 Lt; / RTI > This can be ensured by using heat exchanger W _y2 , in particular as a heat exchanger selected from shell and tube heat exchangers, plates and frame heat exchangers.

In a further preferred embodiment, the device V ₂ is a part of an absorption heat pump. The absorption heat pump then comprises as additional components a condenser, an evaporator and a coolant, wherein the coolant is water.

The condenser is in particular connected to the water desorption unit W _des2 through a conduit and is set up to condense the water at least partially removed from the liquid absorption medium A _{1 * in the} water desorption unit W _des2 . The condenser preferably also comprises a cooling water circuit.

The evaporator is connected to the condenser, in particular via a conduit (which may include throttling means), is connected to the water absorption unit W _abs2 via an additional conduit, and is set up to evaporate the condensed water from the condenser. The evaporator preferably also comprises a pressure of <1 bar, more preferably <0.1 bar, in order to evaporate the condensed water at the lowest possible temperature. The evaporator may further preferably include a device (e.g., a coolant conduit that directs coolant to a space where water is evaporated) that allows heat to be drawn off and condensed water to evaporate.

Finally, the present invention also relates to structure (I) at least one trialkyl phosphate and Q ⁺ A a ^{-, Q + (R 1 O} ) 2 PO 2 -, (Q +) 2 R 2 OPO 3 2 - and _{^{Q + M + R 3 OPO 3}} 2 - a absorbing medium containing at least one salt selected from the group consisting of a mixture of S _{1 *,} and

Here, Q ^& lt ^{; +} & gt ^; is particularly preferably an alkyl group having 1 to 10, preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 4, still more preferably 1 Or a dialkylimidazolium cation having two carbon atoms,

A ^- is R ^* COO ^- is an anion selected from the group consisting _{^{of, -, R'SO 3 -, HSO}} 4 - , and R _"4 SO

R ^* , R ', R ", R ^A , R ^B , R ^C , R ¹ , R ² and R ³ are each independently preferably 1 to 10, preferably 1 to 8, More preferably 1 to 4, still more preferably 1 or 2 carbon atoms,

M ⁺ is directed to an alkali metal ion, preferably Li ^+, K ⁺ or Na ^+, more preferably Na ⁺ or K ⁺ in the absorbent medium A _{1 *} itself.

In a preferred embodiment of the absorbing medium A _{1 *} according to the invention, the salt S in said medium is selected from the group consisting of Q ⁺ A ^- and Q ⁺ (R ¹ O) ₂ PO ₂ ^- , Q ⁺ each independently of one to six, preferably one to four, more preferably dialkyl imidazolium cation having 1 or 2 carbon atoms, a ^- is R ^* COO ^-, R'SO ₃ ^-, and R "SO ₄ ^-, and anions selected from the group consisting of, R ^*, R ^1, R ', R", with R ^a, R are each independently selected from ^B and R ^C 1 to 6, preferably from 1 to 4, More preferably an alkyl group having 1 or 2 carbon atoms.

In a more preferred embodiment of the absorbing medium A _{1 *} according to the invention, the salt S in the medium has the formula Q ⁺ (R ¹ O) ₂ PO ₂ ^- , Q ⁺ is a group in which the alkyl groups are each independently methyl or ethyl R ¹ , R ^A , R ^B and R ^C are each independently methyl or ethyl.

In a more preferred embodiment of the absorbing medium A _{1 *} according to the invention, the salt S in the medium has the formula Q ⁺ (R ¹ O) ₂ PO ₂ ^- , Q ⁺ is 1,3-dimethylimidazolium, Diethylimidazolium, and 1-ethyl-3-methylimidazolium, and R ^A , R ^B , R ^C And R &lt; ¹ &gt; are each independently methyl or ethyl. Subsequently, still more preferably, Q ⁺ is 1-ethyl-3-methylimidazolium and R ^A , R ^B , R ^C And R &lt; ¹ &gt; are each independently methyl or ethyl.

Furthermore, in all of the above embodiments of absorbent media A _{1 *} according to the present invention it is particularly preferred that A ₁ , R ^A , R ^B and R ^C are each independently selected from methyl and ethyl, R ^A = R ^B = R ^C = methyl or R ^A = R ^B = R ^C = ethyl, particularly preferably R ^A = R ^B = R ^C = ethyl.

The liquid absorbing medium A _{1 *} may be present in the form of a pure mixture of a trialkyl phosphate of structure (I) and a salt S. Alternatively, and more preferably, the liquid absorbing medium A _{1 *} may comprise from 65% to 95% by weight, based on the total weight of the aqueous solution, of the total weight of trialkyl phosphates and all salts S, especially of all structures (I) Lt; / RTI &gt; Even more preferably, the total weight of trialkylphosphate and all salts S of all structures (I) in A &lt; _{1 &gt; * is} in the range of from 70 wt% to 90 wt% based on the total weight of the aqueous solution, By weight to 87% by weight.

The ratio of the trialkylphosphate to the salt S of all structures (I) in the liquid absorbing medium A _{1 *} is not further restricted at all. In the liquid absorbent medium A _{1 *} , the ratio of the total weight of trialkylphosphate of all structures (I) to the total weight of all salts S is preferably from 1: 9999 to 1: 9, more preferably from 1: 9999 to 1 : 99, still more preferably from 1: 9999 to 1: 999.

The following figures 1 and 2 show preferred embodiments of the method according to the invention and the device according to the invention.
1 (abbreviated as "Figure 1 &quot;) represents an embodiment of a device V ₂ / V ₁ according to the invention.
The apparatus V ₁ shown in FIG. ₁ has a water absorbing unit W _abs1 where a conduit is connected to it and a conduit is connected to the opposite side _thereof (Optionally an additional heat exchanger W _z1 &Lt; 104 &gt;); A water desorption unit W _des1 comprising a conduit <111> followed by conduits <110>, <112> and <113> to the opposite side and including a heat exchanger W _x1 and a water desorber; And a circuit U ₂ formed from conduits, <111> and <113> or <106>, <111>, <112> and (in each case optionally with conduits). The apparatus of FIG. 1 may also optionally include an additional heat exchanger W _y1 where conduits and <112> are connected and conduits and <111> are connected to the other side thereof. In addition, the device V ₁ also comprises a liquid absorbing medium A ₁ . The medium is located at the one component of water absorbing unit W _abs1, water desorption unit W _des1, and one or more of the circuit U _1. Water absorbing unit W _abs1 <103> is optionally also may comprise a further heat exchanger W _z1 <104>, this liquid absorbing medium A ₁ for example 10 ℃ to 100 ℃, preferably from 15 ℃ to 80 by Deg.] C, more preferably 20 [deg.] C to 50 [deg.] C, and even more preferably 20 [deg.] C to 30 [ Optionally, the circuit U ₂ may further comprise a pump for transporting the liquid absorbing medium A ₁ .
Hereinafter, a method according to the present invention will be described by way of example with reference to the apparatus V ₁ using figure 1:
A stream of a wet gas mixture G ₁ having a temperature of, for example, 2 ° C to 100 ° C (said stream may be wet air, wet natural gas or wet gas mixture - also see FIG. 2 in connection with this option) 101> through is fed to a water absorption unit W _abs1 <103>, from there, into contact with a liquid absorbing medium a ₁ supplied to the conduit <105 via> or conduits <113> water absorbing unit W _abs1 through <103> do. The water absorption unit W _abs1 may be any one of the above-mentioned water absorbers for W _abs1 , in particular a drop-film. In the water absorption unit W _abs1 , when the liquid absorption medium A ₁ supplied through the conduit or via the conduit with the gas mixture G ₁ supplied through the conduit contacts the liquid absorption medium A ₁ , A liquid absorbing medium A ₂ having an increased water content compared to A ₁ and a stream of gas mixture G ₂ discharged through a conduit having a lower water content compared to the wet gas mixture G ₁ are obtained . According to the application example, G ₂ is particularly dehumidified natural gas. Water absorbing unit W _abs1 <103> is optionally also may comprise a further heat exchanger W _z1 <104>, this liquid absorbing medium A ₁ for example 10 ℃ to 100 ℃, preferably from 15 ℃ to 80 by Deg.] C, more preferably 20 [deg.] C to 50 [deg.] C, and even more preferably 20 [deg.] C to 30 [deg.] C. Is then preferably passed through the conduits 106 and 111 and the heat exchanger W _y1 (or the conduits 106, 111 and 114 if the heat exchanger W _y1 is not used) The liquid absorbing medium A ₂ is sent to a water desorption unit W _des1 consisting of a heat exchanger W _x1 and a water _despooler . The water-containing liquid absorbing medium A ₂ may additionally be supplied with heat in the optional heat exchanger W _y1 . Subsequently, water is at least partially removed from the liquid absorbing medium A ₂ in the water desorber, resulting in a liquid absorbing medium A ₃ having a lower water content as compared to the liquid absorbing medium A ₂ . The removed water is then discharged as a liquid or vapor through the conduit, preferably as a vapor, from the water desorber. Subsequently, the liquid absorbing medium A ₃ is discharged from the water _desorber and returned to the water absorption unit W _abs1 . This can also be done directly, that is, through the conduit shown in dashed line in FIG. Alternatively and preferably, the liquid absorption medium A ₃ also through the conduit <112> may be fed to optional heat exchanger W _y1 <107>, where the exchange arbitrary column through conduit <106> W _y1 <107> heat is supplied from a liquid absorption medium, a ₂ is then, via conduit <112> a liquid absorbing medium fed to the a _3, optionally a heat exchanger W _y1 <107> supplied to. When the concentrated liquid absorbing medium A ₃ is fed through the conduit or the water absorbing unit W _abs1 , the medium is reused as A ₁ for at least partly dehumidifying the gas stream in the new cycle.
2 (abbreviated as "FIG. 2 &quot;) shows in a schematic fashion an absorption chiller incorporating device V ₂ . Elements &lt; 101 &gt; to &lt; 114 &gt; are shown for the device V ₂ described in FIG. In addition, the absorption chiller of FIG. 2 is also connected to the water desorption unit W _des2 through the conduit and condenses water at least partially removed from the liquid absorption medium A _{1 *} in the water desorption unit W _des2 And a condenser set up for the condenser. The condenser preferably further includes a heat exchanger, to which cooling water can be supplied.
The absorption chiller shown in FIG. 2 is also connected to the condenser through a conduit (which may optionally include throttling means) and is connected to a water absorption unit W _abs2 through a conduit . The evaporator is set up to evaporate the condensed water from the condenser. Additionally, the evaporator may further preferably further comprise a heat exchanger (e.g., a coolant conduit, particularly with coolant, such as a coolant conduit, The coolant may be sent to an evaporator).
In an embodiment of the method according to the invention (hereinafter referred to as device V ₁ described with reference to Figure 2), the wet gas mixture G derived from the evaporator is introduced into the water absorption unit W _abs1 &lt; . The water removed in the water desorption unit W _des1 is supplied to the condenser through the conduit, where the water is recondensed. A cooling water circuit as a heat exchanger installed in the condenser is optionally used for it as well. The condensed water is then fed to the evaporator through the conduit where the evaporation of water is carried out, especially at low pressure, resulting in a cooling effect. This may optionally also be performed using throttling means. The cooling action is thereby achieved in the evaporator, for example, the coolant can be cooled through the heat exchanger. Subsequently, the generated water vapor is returned to the water absorption unit W _abs1 through the conduit.

The following examples are intended to illustrate the invention without restricting the invention in any way.

< Example >

("EMIM DEP", prepared according to WO 2004/016631 Al) and triethylphosphate ("TEP"; Sigma (Sigma)) to simulate the degradation of 1-ethyl-3-methylimidazolium diethylphosphate Aldrich; CAS No.: 78-40-0) was incubated at 150 占 폚 for 20 minutes.

C1: a mixture of 85% by weight EMIM DEP and 15% by weight H ₂ O;

I1: mixture of EMIM DEP 75 wt%, H ₂ O 15 wt% and TEP 10 wt%;

I2: a mixture of 80% by weight of EMIM DEP, 15% by weight of H ₂ O and 5% by weight of TEP;

I3: a mixture of EMIM DEP 84 wt%, H ₂ O 15 wt% and TEP 1 wt%.

After incubation, the gaseous phase was investigated by mass spectrometry and gas chromatography of the degradation product N-methylimidazole.

The intensity peak area of the N-methylimidazole peak, measured using a flame ionization detector, is directly proportional to the gas phase ratio.

In Sample C1, a pronounced N-methylimidazole peak was observed, while this peak was not present in Samples I1, I2 and I3. This represents an amazing stabilizing effect of triethylphosphate.

Corresponding results are also observed for other trialkyl phosphates.

Claims (24)

At least one trialkyl phosphate and Q ⁺ A of the wet gas mixture G _1, the following structures ^{(I) -, Q + (} R 1 O) 2 PO 2 -, (Q +) 2 R 2 OPO 3 2 - and Q _{^{+ M + R 3 OPO 3 2}} - a gas having at least one salt S with the mixture of a lower water content as compared to the wet gas mixture G ₁ is contacted with a liquid absorbing medium a ₁ comprising a member selected from the group consisting of a mixture G a method for dehumidifying the _two, and a liquid absorption by the medium compared to the a ₁ to give a liquid absorption medium a ₂ having an elevated water content, the wet gas mixture G _1,

Here, Q ⁺ is a dialkyl imidazolium cation, A ^- is _{^{R * COO -, R'SO 3 -}} , HSO 4 - , and R "SO ₄ ^-, and anions selected from the group consisting of, R ^*, R ', R &quot;, R ^A , R ^B and R ^C are each independently an alkyl group, R ¹ , R ² and R ³ are each independently an alkyl group and M ⁺ is an alkali metal ion. The method of claim 1, wherein Q ⁺ is, in particular, a dialkyl imidazolium cation alkyl groups each independently having 1 to 10 carbon atoms, R ^*, R ', R ", R ^A, R ^B, R ^C, R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 10 carbon atoms and M ⁺ = Li ⁺ , K ⁺ or Na ⁺ . According to claim 1 or 2, wherein the salt S is Q ⁺ A ^-, and _{^{Q + (R 1 O) 2}} PO 2 - is selected from the group of a, Q ⁺ a, the alkyl groups each independently of 1 to 6 carbon atoms and a dialkyl imidazolium cation having, a ^- is R ^* COO ^-, R'SO ₃ ^-, and R "SO ₄ ^-, and anions selected from the group consisting ^{of, R *, R 1, R} ', R", R ^A , R ^B and R ^C are each independently an alkyl group having from 1 to 6 carbon atoms. 4. The method according to any one of claims 1 to 3, wherein R ^A , R ^B and R ^C are each independently selected from methyl and ethyl. The method according to any one of claims 1 to 4, wherein the liquid absorbing medium A ₁ is an aqueous solution. The method of claim 5, wherein the liquid absorption medium in A _1, all of the structure (I) trialkyl phosphates and will in all salt S total weight of a total range of 65% to 95% by weight, based on the weight of the aqueous solution of the . 9: claim 1 to claim 6, wherein according to any one of, wherein the liquid absorption medium in A _1, all of the structure (I) ratio of the total weight of the total weight of for every salt S of the trialkyl phosphate of: 9999 to 1 Lt; / RTI &gt; 8. The method according to any one of claims 1 to 7, wherein the method is performed continuously. The following components:
(i) to structure (I) at least one trialkyl phosphate and Q ⁺ A a ^{-, Q + (R 1 O} ) 2 PO 2 -, (Q +) 2 R 2 OPO 3 2 - and Q ⁺ M ⁺ R _³ OPO ^{3 2 -} a liquid absorbing medium containing at least one salt selected from the group consisting of a mixture of S _{1 *,}

(ii) at least one water absorption unit W _abs2 set up to contact the wet gas mixture with the liquid absorption medium A _{1 *}
(iii) at least one water desorption unit W _des2 set up to at least partially remove water from the liquid absorption medium A _{1 *} , comprising a heat exchanger W _x2 , and
(iv) a circuit U ₂ capable of connecting the water absorption unit W _abs2 to the water desorption unit W _des2 and circulating the liquid absorption medium A _{1 *}
A device V ₂ for dehumidifying the wet gas mixture,
Q ⁺ is a dialkyl imidazolium cation and, A ^- is ^{_{R * COO -, R'SO 3 -}} , HSO 4 - , and R "SO ₄ ^-, and anions selected from the group consisting ^{of, R *, R ', R} " , R ^a, R ^B and R ^C are each independently an alkyl group and, R ^1, R ² and R ³ is an alkyl group, each independently, M ⁺ is a device which is characterized in that the alkali metal ion V _2. 10. The method of claim 9, wherein in A _{1 *,} and Q ⁺ is, in particular alkyl groups each independently represents a dialkyl imidazolium cation having from 1 to 10 carbon atoms, R ^*, R ', R ", R ^A, R ^B, R ^C, R ^1, R ² and R ³ are each independently an alkyl group having 1 to 10 carbon atoms, M ⁺ = Li ^+, K ⁺ or Na ⁺ in, the device V _2. 11. Compounds according to any _one of claims 9 to 10, wherein in A _{1 *} , the salt S is selected from the group of Q ⁺ A ^- and Q ⁺ (R ¹ O) ₂ PO ₂ ^- , Q ⁺ a dialkyl imidazolium cation having to 6 carbon atoms, a ^- is R ^* COO ^-, R'SO ₃ ^-, and R "SO ₄ ^-, and anions selected from the group consisting ^{of, R *, R 1, R} ' , R ", R ^a, R ^B and R ^C are each independently an alkyl group having 1 to 6 carbon atoms, V ₂ device. Of claim 9 to 11 according to any one of items, R ^A, R ^B and R ^C is a device V ₂ to each other is independently selected from methyl and ethyl. Article according to any one of claims 12, wherein the liquid absorption medium A _{1 *} is the solution, the device V _2. 14. The method of claim 13, wherein, A _{1 *} is in, any structure (I) trialkyl phosphates and will in all salt S total weight of a total range of 65% to 95% by weight, based on the weight of the aqueous solution of the device V ₂ . 15. A process according to any one of claims 9 to 14 wherein, in A _{1 *} , the ratio of the total weight of trialkylphosphate of all structures (I) to the total weight of all salts S is in the range of from 1: 9999 to 1: 9 Device V ₂ . An absorption heat pump comprising a condenser, an evaporator and a coolant, as an apparatus V ₂ according to any one of claims 9 to 15 and further components, wherein the coolant is water. Use of apparatus V ₂ according to any one of claims 9 to 15 for carrying out the process according to any one of claims 1 to 8. Following structure (I) at least one trialkyl phosphate and the Q ⁺ A ^{-, Q + (R 1 O} ) 2 PO 2 -, (Q +) 2 R 2 OPO 3 2- , and Q ⁺ M ⁺ R _³ OPO ^{3 2 -} a _{1 *} a absorbing medium containing at least one salt selected from the group consisting of a mixture of S,

Here, Q ⁺ is a dialkyl imidazolium cation, A ^- is _{^{R * COO -, R'SO 3 -}} , HSO 4 - , and R "SO ₄ ^-, and anions selected from the group consisting of, R ^*, R ', R ", R ^a, R ^B, R ^C, R ^1, R ² and R ³ are each independently an alkyl group and, M ⁺ is an alkali metal ion, an absorbent medium a _{1 *.} 19. The method of claim 18, wherein Q ⁺ is, in particular alkyl groups each independently of 1 to 10 dialkylimidazolium cation having a carbon atom, R ^*, R ', R ", R ^A, R ^B, R ^C, R ^1, R ² and R ³ are each independently an alkyl group having 1 to 10 carbon atoms, M ⁺ = Li ^+, K ⁺ or Na ⁺ in the absorbent medium a _{1 *.} 20. The method of claim 18 or 19, wherein the salt S is selected from the group of Q ⁺ A ^- and Q ⁺ (R ¹ O) ₂ PO ₂ ^- and Q ⁺ is an alkyl group of 1 to 6 carbon atoms and a dialkyl imidazolium cation having, a ^- is R ^* COO ^-, R'SO ₃ ^-, and R "SO ₄ ^-, and anions selected from the group consisting ^{of, R *, R 1, R} ', R", R ^a, R ^B and R ^C are each independently an alkyl group having 1 to 6 carbon atoms, an absorbent medium a _{1 *.} The absorbing medium A _{1 *} according to any one of claims 18 to 20, wherein R ^A , R ^B and R ^C are independently selected from methyl and ethyl. 22. The absorption medium according to any one of claims 18 to 21, wherein the absorbing medium A _{1 * is an} aqueous solution. 22. The process according to any one of claims 18 to 22, wherein the total weight of trialkyl phosphate and all salts S of all structures (I) ranges from 65% to 95% by weight, based on the total weight of the aqueous solution , Absorption medium A _{1 *} . 24. The process according to any one of claims 18 to 23, wherein the ratio of the total weight of trialkylphosphates of all structures (I) to the total weight of all salts S ranges from 1: 9999 to 1: 9. A _{1 *} .

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